Infectious Diseases 2022

Infectious Diseases 2022

Gross pathology of HPAI virus H5N1

One Health 14 (2022) 14 June, 2022

High pathogenicity avian influenza virus (HPAIV) clade 2.3.4.4b has re-emerged in the United Kingdom in 2021–2022 winter season.
To control the impact of HPAIV epizootic in poultry, up to 2.4 million birds have been culled in the UK during the current season and the strict indoor housing measures applied have also impacted on the marketing of free-range poultry products. Globally, HPAIV H5N1 has also had a wide geographical dispersion, causing outbreaks in Europe, North America, Asia, and Africa, impacting socioeconomic and wildlife conservation. A new study raises awareness of the gross pathological features of HPAIV and subsequently aids disease investigation by defining pathological indicators following natural infection. This study, reports gross pathology of HPAI H5N1 in poultry species (chicken, turkey, pheasant, guineafowl, duck, goose), and captive or wild birds (mute swan, tufted duck, jackdaw, peahen, white-tailed eagle) that tested positive between October 2021 and February 2022. Pancreatic and splenic necrosis were the common pathological findings in both Galliformes and Anseriformes. In addition to the more severe lesions documented in Galliformes, increased detection of pathological changes was noted in a broader range of Anseriformes particularly in domestic ducks, in contrast to those reported in previous seasons with other H5Nx HPAIV subtypes.